Journal Article

Silicon isotope fractionation dynamics during uptake and translocation by various crop species under three soil types

Zhou, Jingjie, Tang, Sheng, Xiao, Han, Ma, Qingxu, Wu, Lianghuan, Sun, Yan, Liu, Mengjiao, Pan, Wankun, Xu, Meng

2022

Overview

PurposeSilicon is important for both plant growth and the soil biogeochemical cycle. Si uptake and accumulation ability varies in plants, which are defined as Si accumulators, intermediates, or non-accumulators. However, the processes governing Si uptake and translocation are not fully understood. Stable Si isotopic signatures may offer new perspectives on the processes involved in the Si biogeochemical cycle.MethodsSi isotopic fractionation between different Si pools was analyzed in Si accumulators (rice, maize), intermediates (cucumber), and non-accumulators (tomato) grown in yellow, black, and cinnamon soils using multi-collector inductively coupled plasma mass spectrometry.ResultsPlants grown in all soil types exhibited 28Si enrichment relative to the soil solution. The degree of fractionation was negatively correlated with silt, clay, free iron oxide (Fed), and crystalline Fe oxide (Fed-Feo) contents, and positively correlated with sand content. The degree of isotope fractionation was species-specific during uptake, in order of rice > maize > cucumber > tomato, while the reverse was true for root–shoot translocation. In addition, isotope fractionation was absent in tomato shoots, contrasting with the Rayleigh-like behavior of the other species.ConclusionFed and Fed-Feo contents affected the H4SiO4 adsorption–desorption process, thereby influencing isotope fractionation between the plants and soil. Species-specific fractionation was attributed to the varying contributions of water flow uptake and the transporter-mediated uptake process. Moreover, the Si transport mechanism within shoots in Si non-accumulators varied from those in accumulators and intermediates. These findings provide insight into Si isotope fractionation dynamics during uptake and translocation.

• Publisher: Springer Nature B.V
• Subject: Accumulators / Biogeochemical cycles / Biogeochemistry / Corn / Cucumbers / Fractionation / Inductively coupled plasma mass spectrometry / Intermediates / Iron oxides / Isotope fractionation / Isotopes / Mass spectrometry / Mass spectroscopy / Plant growth / Rice / Shoots / Silicon / Silicon isotopes / Soil solution / Soil types / Soils / Species / Tomatoes / Translocation / Water flow